#Article Launch Challenge#Choosing an antenna is also an important part of the listening effect. There are many kinds of antennas, some are DIY, some are commercial antennas, some are active antennas, some are passive antennas, how do antennas match your radio?
In fact, the simplest antenna is the long-line antenna, as long as one end of the antenna is thrown out of the window, and the other section is put on the stainless steel rod antenna of the radio, the general length of three or five meters is enough, and it can achieve very good results in short-wave and frequency modulation.
The above kind belongs to the DIY antenna, and more enthusiasts are pursuing more than just a slightly improved effect, the above antenna can only improve the reception of the radio, which is worse than the direct outdoor reception. Some people also think that medium wave can also solve the interference problem, so it is necessary to use a better loop antenna, loop antenna can act on frequency modulation, short wave, medium wave, etc., the frequency range is relatively wide, and the price of a good loop antenna is not cheap. Generally, it is also divided into active and passive, and the difference between the two effects is still relatively large. An active antenna is essentially an antenna system with an amplifier or other signal processing device embedded in the structure. It amplifies the faint signal it receives and then transmits it to the receiver. Active antennas can be divided into two types: resonant active antennas and non-resonant active antennas.
Passive antennas, on the other hand, do not have built-in amplifiers or other signal processing devices, and do not amplify or process the received signal, but directly transmit the signal to the receiver. Generally, active loop antennas are suitable for radios, while passive loop antennas are suitable for receiving devices such as SDR. For example, the common youloop is actually an SDR receiving antenna, but it will have unexpected effects when connected to the radio, so its use has been expanded.
In addition, the active antenna has the function of amplification, and also has the function of filtering, filtering out some clutter to prevent the amplification of clutter, while the passive antenna generally does not have this function, so the passive antenna generally appears to be cheaper. One of the annoyances of active antennas is that they need to add batteries, which will leak over time and then damage your expensive antenna circuit board.
Once the antenna is erected in a better position and the electromagnetic environment is cleaner, it is more susceptible to co-channel interference, and whether the radio has synchronous detection is more important at this time.